diff options
| author | Ian Jackson <Ian.Jackson@eu.citrix.com> | 2012-11-14 11:30:34 +0000 |
|---|---|---|
| committer | Ian Jackson <Ian.Jackson@eu.citrix.com> | 2012-11-14 11:30:34 +0000 |
| commit | dfa0cb6a14b3c835e643f56b620137b5aff3e1c1 (patch) | |
| tree | 72a632131081ca9f759f9b0a38d333cb5a9bae27 /xen/common/domain.c | |
| parent | b46c24edb7b8acba387b8621f867b7d4c5fce1b3 (diff) | |
| download | xen-dfa0cb6a14b3c835e643f56b620137b5aff3e1c1.tar.gz xen-dfa0cb6a14b3c835e643f56b620137b5aff3e1c1.tar.bz2 xen-dfa0cb6a14b3c835e643f56b620137b5aff3e1c1.zip | |
VCPU/timers: Prevent overflow in calculations, leading to DoS vulnerability
The timer action for a vcpu periodic timer is to calculate the next
expiry time, and to reinsert itself into the timer queue. If the
deadline ends up in the past, Xen never leaves __do_softirq(). The
affected PCPU will stay in an infinite loop until Xen is killed by the
watchdog (if enabled).
This is a security problem, XSA-20 / CVE-2012-4535.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Diffstat (limited to 'xen/common/domain.c')
| -rw-r--r-- | xen/common/domain.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/xen/common/domain.c b/xen/common/domain.c index 0e3e36aa1b..12c8e24e09 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -903,6 +903,9 @@ long do_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg) if ( set.period_ns < MILLISECS(1) ) return -EINVAL; + if ( set.period_ns > STIME_DELTA_MAX ) + return -EINVAL; + v->periodic_period = set.period_ns; vcpu_force_reschedule(v); |